There are various types of power supplies which have an input switch and a plurality of output voltages. The voltage level at the outputs are determined by modulating the pulse width or duty cycle of the input switch. That is, when the value of the output voltages are low, the duty cycle of the input switch is increased to raise the output voltages.
The present invention provides a regulator to perform this operation by feedback from the output and is accomplished in that the controlling voltage in the regulator is always the lowest voltage or the most heavily loaded output.